External Validation of 3 Prediction Models for Mortality in Out-of-Hospital Cardiac Arrest Survivors: A Retrospective...

Predictive models such as the Cardiac Arrest Survival Score (CASS), FACTOR score, and Survival After ROSC in Cardiac Arrest (SARICA) have been developed to estimate in-hospital mortality in out-of-hospital cardiac arrest survivors. This study aims to externally validate and compare their predictive performance to determine their clinical utility upon emergency department admission.

This retrospective multicenter cohort study included out-of-hospital cardiac arrest patients admitted to the National Taiwan University Hospital and its branches between January 2016 and March 2024. The outcome was in-hospital mortality following intensive care unit admission. We assessed the CASS, FACTOR, and a modified SARICA (mSARICA) score using the area under the receiver operating characteristic curve, positive predictive value, and negative predictive value. The SARICA score was adapted into the mSARICA score to ensure outcome consistency. The positive predictive value threshold was set at 0.85 to minimize false-positive predictions.

The study included 1456 patients, of whom 495 (34%) survived to discharge and 961 (66%) died before discharge. The area under the receiver operating characteristics for CASS, FACTOR, and mSARICA were 0.684 (95% CI, 0.654-0.713), 0.677 (95% CI, 0.647-0.706), and 0.711 (95% CI, 0.682-0.739), respectively, with no significant differences among them. The optimal cutoff values were >17.5 for CASS, ≥69.25 for FACTOR, and <1.0 for mSARICA. While CASS and FACTOR demonstrated similar sensitivity, specificity, and negative predictive value, mSARICA exhibited significantly higher sensitivity, lower specificity, and higher negative predictive value.

All scores demonstrated fair but not excellent discrimination for in-hospital mortality. When minimizing false positives is critical, CASS and FACTOR may be preferable, whereas mSARICA offers greater sensitivity.